Coal or rock drill.



No. 659,!39. Patented Got. 2, new. J. Emma.

COAL UR ROCK DRILL.

(Application filed July 8, 1898. Rene'wed Mar. 15, 1900.

(No Model.)

WITNESSES i ATTORNEYS 'llivirsn Smirns JAMES EAGlLN, OF WYOMING, PENNSYLVANIA.

COAL. OR ROCK DRILL.

SPECIFICATION forming part of Letters Patent No. 659,139, dated October 2, 1900.

Application filed July 8, 1898. Renewed March 15, 1900. Serial No. 8.855. N modehi as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specificaman.

My invention relates to coal and rock drills, particularly to the drill and bit used in drilling-machines in which the stem or shank of the drill is screw-threaded and works through a nut inovably secured to thesupport.

The invention consists in the connection (which is an improvement on Patent No. 328395 by James S. Loftus and which is now owned by myself) and in the cutter or bitand means of securing the same to the extensionbar.

Reference is to be had tothe accompanying drawings, which form a. partof this specification, and in which like numerals of reference refer to like parts in the diiferent figures.

Figure l is an elevation of thedrill and bit. Fig. 2 is an end view or plan of the bit. Fig. 3 is a side View or elevation of the bit. Fig. 4 is a View of the mole end of the connection. Fig. 5 is a view of the connection, the dotted lines indicating the interiorof the socket and the male end of the connection in place in the socket. Fig. 6 is an elevation of the front of the socket with male end in position, the dotted .lines indicating the interior. Fig. 7 is a cross-section of the end of the extension-bar. with bit in place, showing the method of holding the bitin place. Fig. 8 is an elevation of the end of the drill or-extension-bar where the bit is secured. Fig. 9 represents two edge elevations 0t the, cutting end of 'the bit, the dotted .lines showing the oppositely-inclined planes of the two hevels.

l is the drill, 2 the male end of theconnection, and 3 the slot in the socket to receive the pin 5, which is secured to the male end of the connection. I

l is an elongation or enlargement of the slot at its lower end to prevent the breaking strain on the pin after the socket and male end of the connection have become somewhat worn by use.

Gis the reverse-curve bit; 7, the shank of the bit; 8, the point of curvature; 9, the point of reverse curvature, and 10 the hole in the shank of the bit to receive the bolt 12, which passes through the hole 10 in the bit and the hole 11 in the end of the drill, being held rigidly in place .by the nut 13.

ii is the flattened end of the drill or extension-bar l, with its edges turned over to form the lips 15, under which the shank of the-bit 7 passes.

The manner of connecting the drill,so as to form any desired length of convenient lengthened pieces, I do not claim as new. My improvement is one, however, which has made itself manifest by experience with the above-noted patent, which I now own. It has been demonstrated that after some use the socket and also the male end of the connection become worn, so that the pin 5 is subjected to a breaking strain which causes a great deal of trouble andlinconvenience when the drill is withdrawn from the hole. trouble I obviate by the elongation or enlergement 4 of the slot 3 at its lower end'et the position of the pin when the male end of the connection is at its proper position in the socket.

The cutter or bit I make in the form of a reverse curve or partial S shape in cross-section, having its point of reverse curvature at or near the center of said bit. The cutting edge is formed by beveling off the bit half on one side and half on the other side, each bevel taking in one of the con vexed portions the two beveled portions will meet at the center of the cutting edge-that is, at the point of the reverse curvature-and form a central entering-point 9 and two entering and en];- ting points 8 at the edges of the bit, giving the cutting edge an escalloped form infside elevation. It will be observed that ahitof this form may be sharpened readily and wit h ontother tools than a file, the bit lasting until it is entirely used up. My object is to overcome an existing source of trouble in the ordinary form of' coal and rock drills-11. (1.,

formed by the S shape of the bit, whereby This the necessity of having a blacksmith to sharpen the bit or cutter, which is a source of expense to the miner; also, the keeping of the cutter or hit in its proper shape when sharpened with a file by the operator, (a difficult matter for a miner unskilled in the use of tools.) By using the reverse-curve bit or cutter it is only necessary to tile it from each side, filing each time from the convex side, as the center ot the bit is necessarily at the pointof reverse curvature. and the outer edge of the bit will be brought to a point, thus saving the blacksmiths charge for sharpening and giving a bit whose cutting qualities are far in excess of the other styles now employed.

An essential Feature lies in the fact that each bevel cuts straight across and is coextensive with one of t he two convcxcd portions,

lips 15, as shown in Figs. 7and 8,-thus forming a rigid socket, one which may be readily cleaned, also one from which the bit maybe I cutting straight across one of the two conthe two l)(\tl-5lll0@llhf.fttl the ctmtcrand their planeshein; oppositely inclined to the axis t -ilnirpcning the bit, no cat'cl'ttl manipulation of the tile or the bit being required.

The socket to hol l'the bit I make by flattening one end ot' the cxtensiou-bar of the This enables a common llat' il'lll and turning its edges over to form the vexed portions of the body portion, the two bevels being upon opposite sides of the bit and being oppositely inclined and meetingat the axial center til the bit, whereby threc enteringand'cutting pointsarc formed, one midway the cutting edge and one at each end thereof, for the purposes set forth.

In testimony whereof I atTix my signature in presence of two witnesses.

.I A M ES RAG EN.

Witnesses:

S. P. PENN, l-. ll. KYTE. 

